Atomic Structure and Average Atomic Mass Quiz

What is the charge of a neutron?

• +1

• 0

• -1

• It depends on the isotope

Which subatomic particle is directly involved in chemical reactions?

• Proton

• Neutron

• Electron

• All of the above

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What does the atomic number of an element represent?

• The number of neutrons

• The number of protons

• The total number of protons and neutrons

• The number of electrons in a neutral atom

How is the average atomic mass of an element calculated?

• By adding the masses of all isotopes

• By averaging the mass numbers of all isotopes

• By multiplying the mass of each isotope by its natural abundance and then summing these values

• By dividing the mass number by the atomic number

What unit is used to express atomic mass?

• Grams

• Kilograms

• Atomic mass units (amu)

• Daltons

Which of the following is true about isotopes?

• They have different numbers of protons

• They have different numbers of electrons

• They have different numbers of neutrons

• They are different elements

What is the average atomic mass of an element that has 2 isotopes with masses of 10 amu and 11 amu, and natural abundances of 20% and 80% respectively?

• 10.2 amu

• 10.8 amu

• 11.0 amu

• 20.8 amu

In the Bohr model of the atom, electrons:

• Move in random paths around the nucleus

• Are stationary

• Move in fixed orbits around the nucleus

• Are directly attached to the nucleus

What is the significance of the quantum mechanical model of the atom?

• It describes electrons as particles orbiting the nucleus

• It accurately predicts the exact path of an electron around the nucleus

• It treats electrons as waves and particles, and describes their behavior in terms of probabilities

• It is a simplified version of the Bohr model

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Which of the following best describes the nucleus of an atom?

• It contains only protons

• It is positively charged and contains protons and neutrons

• It is negatively charged and contains electrons and neutrons

• It contains all the mass of the atom but no charge

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